There is now known a fuel injection pump for a combustion engine having a cam drive arranged to control at least one adjustable pump piston, said cam drive being rotatable relative to associated elements for adjusting the timing of the fuel injection by means of said piston which cooperates with a feed pump to provide an rpm-dependent pressure against the force of at least one resilient member, so that the initial tension of at least one other resilient member can be increased after starting.
The invention relates to a fuel injection pump which can be adjusted to move the timing at the beginning of the injection operation forward and back during warm-up and warm running to provide the best timing of the fuel injection for the temperature of the engine. In a known fuel injection pump of this type an element which raises the spring tension functions to delay the beginning of the injection and is dependent on the rpm. While this known element makes possible an advanced or earlier injection during starting and idling rpm's, the element is moved to a second position after the engine once reaches an rpm that is higher than its idling rpm. An advanced position of such element has the advantage in starting that it provides a quick start, but such a construction also has the disadvantage that once the engine is warm the operation thereof is not only very rough, but is very noisy as well. The temperature of the engine, in conjection with the beginning of the fuel injection process, has a decided effect on characteristics of combustion, such as noise, emission of poisonous gases, and excessive fuel consumption. The known systems are not sufficiently versatile to allow for a modification of temperature at the beginning of the fuel injection with respect to the rpm of an engine.